BACKGROUND: Advanced parental age has been suggested as a risk factor for Alzheimer's disease (AD) as well as for other psychiatric disorders. In the present investigation, a sample of gerontopsychiatric patients was examined for a possible parental age effect. STUDY POPULATION AND METHODS: Eighty-three patients with AD, 154 elderly patients with depressive episodes, and 48 comorbid patients (AD and depressive episode) as well as 107 age-matched healthy control subjects from the general population were included in the investigation. Information on the years of birth of the parents was derived from personal or family history information. RESULTS: The mean maternal and paternal ages at the time of birth of the index subject were not significantly different for the different diagnostic subgroups or for the control sample. CONCLUSION: There was no evidence in our sample that advanced parental age increases the risk of AD or depression in the elderly.